FIRE PROTECTION IN REFURBISHED BUILDINGS Chris Hall – Commercial Development Officer, SIDERISE
Buildings change and evolve over time, adapting to the changing needs and requirements of tenants. But when buildings change due to refurbishment, compartmentation can be comprised impacting the fire safety of a building.
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ontractors creating holes in smoke-rated walls or floors due to modifications in building services can leave buildings vulnerable to fire which can potentially take hold and spread more quickly. With fire protection paramount in any new layout, the role of fire stop systems must be made a priority with breaches repaired before occupancy. It’s important to first understand the role of fire stops, which are principally to provide continuation to a fire resistant compartment wall/floor where gaps have occurred due to an imperfection, fit or design tolerance between elements or components and are crucial to preventing the passage of flames and noxious gases travelling from one compartment floor or room to the next. A fire in large high-rise building, for example, can generate large quantities of smoke that tends to spread vertically throughout the building, even if the fire is contained to one room. In high-rise buildings, when the gap/ cavity at the perimeter edge between the floor and curtain wall is not properly sealed, flames and smoke can spread vertically to higher floors, and horizontally from one room to the next. Addressing these gaps/cavities by properly installing firestops maintains the floors’ fire compartmentation of the building. This delays vertical smoke-spread and reduces the risk of smoke-related injury in the upper floors of the building, and adjacent rooms.
While a building’s original design may have been certified fire safe, refurbishments, retrofits and alterations can create challenges for firestops and cavity barrier systems which in turn will have an impact on fire safety.
Compression and recovery The perimeter barrier firestops seal the gap between the edge of the compartment wall or floor slab and external façade. Due to project designs and site tolerances, this linear gap can be variable, so the firestop system used needs to have a degree of ‘dynamic’ movement capability – compression and recovery – in order to accommodate serviceability movement, and more significant movement under fire load.
It’s critical the firestop system does this in combination with the primary functional requirement, which is to maintain continuity of fire resistance between the compartment floor and the external wall. The installed firestop system needs to match the same period of fire resistance as the compartment floor. The most effective fire-stopping products combine a number of material features – density, thickness, resin content, fibre structure and controlled compression – which together determine the resistance properties.
RRNews - Issue 37
Many buildings are divided into compartments to restrict fire spread. Where an external wall abuts a compartment wall or floor, fire stops are required between the external wall and the compartment wall or floor to restrict fire spread through the junction.
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Change of use While a building’s original design may have been certified fire safe, refurbishments, retrofits and alterations can create challenges for firestops and cavity barrier systems which in turn will have an impact on fire safety. This issue can be compounded if there is a low understanding on building sites of the requirements for fire stopping and cavity barriers in terms of where and what is needed, and how they are installed. A contractor will be an expert in plumbing or electrical installations but may not have the expertise or experience in fire stopping or cavity barriers. They may have to cut through these products without knowing the implications, whilst the people who do understand the implications may be completely unaware.